Mount Rainier National Park
|Mount Rainier National Park (Rene Frederick/Digital Vision/Getty)|
Mt. Rainier is so big, it makes its own weather. At an elevation of 14,410 feet, the mountain lies only 100 miles east of the Pacific Ocean in the heart of a mild, maritime climate. But the clouds that often collect around the mountain, forming a cap on the summit, clearly indicate a change in weather.
Large mountains like Rainier make their own weather by forcing incoming air masses upward as they strike the mountains. As the air rises it cools at an average rate of 3.5 degrees Fahrenheit per 1,000 feet, forming clouds and increasing precipitation as the air rises over the mountains. On the leeward side of the mountains the air descends down slope, warms, and increases the amount of water vapor it can hold. This leeward side of the mountain receives less precipitation, in what is called a "rain shadow."
The heaviest snowfall on Mt. Rainier occurs between the 5,000- and 11,000-foot elevations. Year-round weather stations are located at Longmire (2,761 feet), Ohanapecosh (1,949 feet), and Paradise (5,400 feet) ranger stations for recording precipitation, temperature, wind direction, and cloud cover. The Paradise Ranger Station is known for its snowfall, holding a record for the most accumulated snowfall in a single year1,122 inches (93.5 feet) of snowfall in 1971-72.
Mountain weather is very changeable. Wet, cold weather can occur any time of the year. While late-July and August can be the driest, warmest time of the year, summer can also be wet and cool. Snow will remain at the 5,000- to 8,000-foot elevation well into mid-July. Hikers and mountain climbers should be prepared for changing weather. Pay attention to weather forecasts, both short-term and long range, avalanche warnings, and special weather alerts. Bring extra clothing, rain gear, and a tent for protection against storms that may occur at any time of year. Know the weather forecast and plan your trip accordingly.
Annual average precipitation:
Average annual snowfall at Paradise: 635"
Maximum snowfall at Paradise in one year:
1,122", winter 1971-1972
Minimum snowfall at Paradise in one year:
313", winter 1939-1940
Average summer low/high temperatures:
Longmire: 44/68 degrees F
Paradise: 41/60 degrees F
Ohanapecosh: 47/75 degrees F
Details mentioned in this article were accurate at the time of publication